It's actually use thermal expansion function. There is a bimetallic strip in a room which it heated, it's bend to a side which has a different coefficient with the another one. When it's bend, it's connect an electricity then a fire sprinkler system can sprinkler some water.That's the first advantage. Let's see the second one.
A person want to fit a metal tire to a wooden wheel but the metal tire is a little bit smaller than the wooden wheel. So, he/she heat up the metal tire and now the metal tire bigger than the wooden wheel, directly he/she fit the hot metal tire to the wooden wheel (of course not with hand), wait a moment while the metal tire do contraction then the metal tire will be fit up to the wooden wheel.Here's the picture:
Reference: Science Matters Volume A by Joan Fong, Lam Peng Kwan, Eric Lam, Christine Lee, and Loo Poh Lim.
Okay, that's it, thanks for your visit, have a nice day!